This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The experiments aim to elucidate the key parameters that control the interactions between cytoskeletal filamentous proteins (the biopolymers neurofilaments, microtubules, and filamentous actin), and lead to hierarchical supramolecular structures on the nanometer to micron scale. The biopolymer assemblies will be characterized in powder and oriented samples using x-ray capillaries and microchannels, respectively. The synchrotron structure studies of oriented assemblies in microchannels should reveal the nature of the ordering of the cross-linking, or, in the case of neurofilaments, protruding sidearm proteins, and provide important insight into the origin of interfilament interactions. The proposal?s unique approach combines synchrotron x-ray scattering, which yields statistically averaged structures in reciprocal space, and real-space imaging with electron and optical microscopy, to probe and solve non-crystalline structures of biomacromolecular assemblies (where protein crystallography techniques do not apply). The learned concepts should lead to the exciting possibility of developing advanced nanometer scale materials for nanoscience applications in the electronic, chemical, and pharmaceutical industries.